Gas barrier film laminate

ABSTRACT

Disclosed is a gas-barrier film laminate having at least two gas-barrier film layers laminated via an adhesive layer, wherein the gas-barrier film layer has a substrate film, and at least one constitutive unit layer comprising an anchor coat layer and an inorganic thin film layer formed on at least one surface of the substrate film in that order, and wherein the number of the bubbles having a diameter of at least 0.5 mm and the impurities having a diameter of at least 0.5 mm existing between the gas-barrier film layers is at most 3 in total per 100 cm 2 .

CROSS-REFERENCE TO PRIOR APPLICATION

This is the U.S. National Phase Application under 35 U.S.C. §371 ofInternational Patent Application No. PCT/JP2007/072192 filed Nov. 15,2007, which claims the benefit of Japanese Patent Application No.2006-309871 filed Nov. 16, 2006, both of them are incorporated byreference herein. The International Application was published inJapanese on May 22, 2008 as WO2008/059925 A1 under PCT Article 21 (2).

TECHNICAL FIELD

The present invention relates to a film laminate excellent ingas-barrier property, appearance and interlayer adhesiveness.

BACKGROUND ART

As a gas-barrier film laminate comprising a gas-barrier film for use forpackaging materials, for example, heretofore known are one produced bylaminating layers of transparent resin layer/oxide thin filmlayer/moisture-absorbing resin layer via an adhesive layer for thepurpose of enhancing the water vapor-barrier property thereof (seePatent Document 1); one produced by laminating at least two resin layersand laminating an organic/inorganic hybrid layer formed according to asol-gel process between the layers for the purpose of enhancing the heatresistance and the gas-barrier property thereof (see Patent Document 2),etc.

In case where gas-barrier films are laminated via an adhesive layer inthe manner as above and when the adhesive layer is cured by heating,then various gases such as carbon dioxide are formed during curingreaction or owing to the later influence of moisture in the substrate orin air, whereby the laminate structure may be whitened owing to bubblingor foaming to occur between the laminated gas-barrier films, thereforecausing a problem in point of the appearance thereof. When the bubblingor foaming is too much, then it may cause the reduction in thegas-barrier property and the reduction in the lamination strength.

In particular, in case where an isocyanate-based adhesive is used, areaction gas such as carbon dioxide may be often generated with thecuring reaction during curing, and in case where gas-barrier films aremulti-laminated, there occurs a problem in that a large quantity ofbubbles are generated.

In addition, in case where gas-barrier films are multi-laminated, thereoccurs another problem in that air remaining in the interface betweenthe adhesive and the gas-barrier film may form bubbles to worsen theappearance of the laminate.

Regarding the problem, in Patent Document 3, the adhesive composition isspecifically noted, and a film that has solved the problem of foamingwhitening and bubbling contamination by removing the influence ofmoisture thereon is disclosed.

The film could improve the intended property mentioned above in somedegree, but is still insufficient in point of the gas-barrier propertyand the lamination strength (interlayer adhesiveness) of the laminate,and it is desired to improve this.

[Patent Document 1] JP-A 2003-249349

[Patent Document 2] JP-A 2004-136466

[Patent Document 3] JP-A 2006-51751

DISCLOSURE OF THE INVENTION Problems that the Invention is to Solve

The present invention relates to a gas-barrier film laminate in whichthe generation of bubbles and impurities between the gas-barrier filmsis noticeably reduced and which is excellent in the gas-barrier propertyand the interlayer adhesiveness.

Means for Solving the Problems

Specifically, the present invention relates to:

(1) a gas-barrier film laminate having at least two gas-barrier filmlayers laminated via an adhesive layer, wherein the gas-barrier filmlayer has a substrate film, and at least one constitutive unit layercomprising an anchor coat layer and an inorganic thin film layer formedon at least one surface of the substrate film in that order, and whereinthe number of the bubbles having a diameter of at least 0.5 mm and theimpurities having a diameter of at least 0.5 mm existing between thegas-barrier film layers is at most 3 in total per 100 cm²;

(2) a method for producing a gas-barrier film laminate comprising:

(a) a step of forming, on a substrate, at least one constitutive unitlayer comprising an anchor coat layer and an inorganic thin film layerin that order, thereby forming a gas-barrier film layer,

(b) a step of laminating at least two formed gas-barrier film layers viaan adhesive layer, and

(c) after or simultaneously with the lamination of gas-barrier filmlayers, a step of heating it or irradiating it with energy rays in avacuum atmosphere at not more than 1000 Pa; and

(3) a method for producing a gas-barrier film laminate comprising:

(a) a step of forming, on a substrate, at least one constitutive unitlayer comprising an anchor coat layer and an inorganic thin film layerin that order, thereby forming a gas-barrier film layer, and

(b) a step of laminating at least two formed gas-barrier film layers viaan adhesive layer comprising an epoxy-based resin.

Effect of the Invention

According to the present invention, there is provided a gas-barrier filmlaminate in which the generation of bubbles and impurities between thegas-barrier films is noticeably reduced and which is excellent in thegas-barrier property and the interlayer adhesiveness.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is described in detail hereunder.

Gas-Barrier Film Laminate

The gas-barrier film laminate of the present invention has at least twogas-barrier film layers laminated via an adhesive layer, wherein thegas-barrier film layer has a substrate film, and at least oneconstitutive unit layer comprising an anchor coat layer and an inorganicthin film layer formed on at least one surface of the substrate film inthat order, and wherein the number of the bubbles having a diameter ofat least 0.5 mm and the impurities having a diameter of at least 0.5 mmexisting between the gas-barrier film layers is at most 3 in total per100 cm².

The gas-barrier film laminate of the present invention comprises atleast two gas-barrier films laminated via an adhesive layer.

For imparting the adhesive layer, employable is any of a method ofapplying an adhesive onto the surface of the gas-barrier film layer, ora method of laminating an adhesive film between the gas-barrier films.

As the adhesive for the adhesive layer, usable are thermosettingadhesives, energy ray-curable adhesives, etc.

The thermosetting adhesive includes, for example, polyester-based resin,urethane-based resin, acrylic resin, ether-based resin, phenolic resin,furan-based resin, urea-based resin, melamine-based resin, epoxy-basedresin, etc. The energy ray-curable adhesive includes, for example,urethane-based resin, polyester-based resin, etc. Of those, preferred isat least one selected from urethane-based resin, epoxy-based resin,polyester-based resin, and acrylic resin. Further from the viewpoint ofreducing the generation of bubbles, more preferred are epoxy-based resinand acrylic resin; and even more preferred is epoxy-based resin.

One concrete example of the adhesive composition comprises, for example,an urethane (meth)acrylate ingredient, an epoxy (meth)acrylateingredient, an alicyclic (meth)acrylate ingredient, and an optionalpolymerization initiator.

The adhesive is not limited to a thermosetting resin, but may also be athermoplastic resin such as polyimide, polyether imide, polyetheramide-imide, etc.

The adhesive resin may be used singly, or two or more different types ofthose resins may be combined and used.

Preferably, the adhesive layer has a moisture permeability at 40° C. and90% RH of at most 1000 g/m²/24 hr through the thickness thereof of 1 μm,from the viewpoint of enhancing the gas-barrier property of theinorganic thin films. More preferably, the moisture permeability is atmost 300 g/m²/24 hr.

Also preferably, the oxygen permeability through the adhesive layer at25° C. and 90% RH is at most 1000 ml/m²/24 hr/MPa, from the viewpoint ofenhancing the gas-barrier property of the inorganic thin films, morepreferably at most 500 ml/m²/24 hr/MPa, even more preferably at most 100ml/m²/24 hr/MPa. From the above-mentioned viewpoint, preferably in thepresent invention, the water vapor permeability (moisture permeability)through the gas-barrier film is at most 0.2 g/m²/24 hr at 40° C. and 90%RH and the oxygen permeability through the adhesive layer falls withinthe above range.

Further, in the adhesive layer, preferably used is an adhesive having alarge number of aromatic rings such as metaxylenediamine skeletons,paraxylenediamine skeletons and bisphenol skeletons and capable ofmaking the adhesive layer have a gas-barrier property. Further, forpreventing the generation of bubbles therein after the formation of thegas-barrier film laminate, an epoxy-based resin is preferably used asthe adhesive.

Examples of the epoxy-based resin having the advantage of gas-barrierproperty and prevention of bubble formation include epoxy resin having aglycidylamine moiety derived from metaxylylenediamine, epoxy resinhaving a glycidylamine moiety derived from1,3-bis(aminomethyl)cyclohexane, epoxy resin having a glycidylaminemoiety derived from diaminodiphenylmethane, epoxy resin having aglycidylamine moiety derived from paraaminophenol, epoxy resin having aglycidyl ether moiety derived from bisphenol A, epoxy resin having aglycidyl ether moiety derived from bisphenol F, epoxy resin having aglycidyl ether moiety derived from phenol novolak, epoxy resin having aglycidyl ether moiety derived from resorcinol, etc. Above all, morepreferred are epoxy resin having a glycidylamine moiety derived frommetaxylylenediamine and/or epoxy resin having a glycidyl ether moietyderived from bisphenol F from the viewpoint of the gas-barrier propertythereof.

Preferably, the epoxy resin is in the adhesive layer in an amount of atleast 50% by mass, from the viewpoint of the effect of the presentinvention, more preferably at least 60% by mass, even more preferably atleast 80% by mass, still more preferably at least 100% by mass.

The curing agent for the epoxy resin is preferably a reaction product ofthe following (A) and (B) or a reaction product of the following (A) and(C) or a reaction product of the following (A), (B) and (C) from theviewpoint of the effect of the present invention; these may be usedsingly and two or more of these may be used as combined.

(A) Metaxylenediamine or paraxylenediamine;

(B) Polyfunctional compound having at least one acyl group capable offorming an amide group moiety through reaction with a polyamine to forman oligomer;

(C) Monovalent carboxylic acid having from 1 to 8 carbon atoms and/orits derivative.

Concretely mentioned are metaxylylenediamine or paraxylylenediamine, andmodified reaction products with epoxy resins or monoglycidyl compoundsusing them as a starting material, modified reaction products thereofwith alkylene oxides having from 2 to 4 carbon atoms, addition reactionproducts thereof with epichlorohydrin, reaction products thereof withpolyfunctional compounds having at least one acyl group capable offorming an amide group moiety through reaction with these polyamines toform oligomers, and reaction products of polyfunctional compounds havingat least one acyl group capable of forming an amide group moiety throughreaction with these polyamines to form oligomers, with monovalentcarboxylic acids having from 1 to 8 carbon atoms and/or derivativesthereof, etc.

Also usable is a water-base adhesive comprising, as the main ingredientthereof, an anionic water-base polyurethane emulsion having, as the mainskeleton thereof, a polyolefin-based polyol prepared through reaction ofa polyolefin-based polymer and a polyisocyanate, and containing, asother ingredients, amines and water-soluble high-boiling-point organicsolvents, etc. The water-base adhesive is effective for adhesion ofpolyolefin-based resin materials and polyester-based resin materials.The water-base adhesive may contain, if desired, one or more water-baseplastic emulsions selected from polyether-based polyurethane emulsion,polyester-based polyurethane emulsion, polycarbonate-based polyurethaneemulsion, polyacrylate ester emulsion, ethylene/vinyl acetate copolymeremulsion, styrene/butadiene copolymer emulsion, polyvinyl acetateemulsion, etc.

The viscosity of the adhesive layer may be controlled by controlling theresin amount in the adhesive composition and, in addition to it, also bycontrolling the temperature and the time in coating with the adhesivevarnish to thereby control the remaining solvent amount, and in case ofa thermosetting resin, further controlling the semi-cured conditionthereof.

Adding inorganic particles or organic particles to the adhesive layermay be effective for finely dispersing the gas taken in the resin forthe adhesive layer in mixing it or generated therein during reaction tothereby disperse the bubbles in the adhesive layer into those having asize of at most 0.01 μm, whereby a gas-barrier laminate having a goodappearance can be produced.

Concretely, inorganic particles of crystalline silica, amorphous silica,aluminium hydroxide, alumina, aluminium nitride, boron nitride, antimonytrioxide or the like, or organic particles of silicone powder or thelike may be added to the adhesive layer in preparing it. One or moredifferent types of the inorganic particles and the organic particles maybe used either singly or as combined. As the inorganic particles,preferred are silica particles from the viewpoint of the availabilityand the stability.

From the viewpoint of the hot water resistance and the cohesive failureresistance thereof, the mean particle size of the inorganic particles orthe organic particles is preferably from 0.005 to 50 μm, more preferablyfrom 0.01 to 20 μm, even more preferably from 0.05 to 10 μm. The contentof the inorganic particles and/or the organic particles in the adhesiveis preferably from 0.01 to 30% by mass, more preferably from 0.05 to 10%by mass, from the viewpoint of the defoamability and the adhesionstrength of the layer.

In addition to the above, if desired, any other additives may be furtheradded to the adhesive, such as curing promoter, coupling agent,inorganic ion adsorbent, polymerization initiator, tackifier, wettingagent, etc.

The thickness of the adhesive layer comprising adhesive is preferablyfrom 0.2 to 30 μm, more preferably from 0.5 to 10 μm from the viewpointof the adhesion strength and the workability thereof.

In case where an adhesive film is used and when an adhesive film is usedalone, its thickness is preferably from 1 to 100 μm, more preferablyfrom 5 to 50 μm from the viewpoint of the workability thereof. In casewhere a base film is used, its thickness is preferably at least 3 μm,more preferably from 5 to 100 μm from the viewpoint of the barrierproperty thereof; and the overall thickness of the base film along withthe adhesive layer formed on both surfaces thereof is preferably from 6to 160 μm, more preferably from 10 to 100 μm or so. In this case, thethickness of the adhesive layer on both surfaces of the base film may bethe same or different.

The adhesive film preferably has a low modulus of elasticity forreducing the thermal stress to result from the thermal expansioncoefficient difference between the film and the gas-barrier film.Preferably, the storage modulus, as measured with a dynamicviscoelasticity measuring device, of the film is from 10 to 2000 MPa at25° C. and is from 3 to 50 MPa at 260° C.

Concretely, for example, the adhesive film comprises at least oneselected from epoxy-based resin, acrylic resin, epoxy group-containingacrylic copolymer, phenolic resin, epoxy resin curing agent, andsemi-cured epoxy-based thermosetting resin comprising epoxy resin curingagent.

In the present invention, preferably, the surface roughness Rms of theadhesive layer or the adhesive film is from 0.05 to 40 μm, for thepurpose of bettering the defoamability of removing the bubbles to formbetween the film in curing, more preferably from 0.10 to 20 μm, evenmore preferably from 0.2 to 20 μm. The level of the surface roughnessRms may be attained, for example, according to a method of addinginorganic particles or organic particles, or mixing two or moredifferent types of resins, or mechanically roughening the surface; andthis may be determined according to the method to be mentionedhereunder.

In the present invention, the gas-barrier film laminate may be producedby laminating at least two, preferably at least three gas-barrierlaminate layers; and from the viewpoint of the workability thereof,preferably, the above-mentioned adhesive layer (adhesive or adhesivefilm) is provided on the surface of the inorganic thin film or theprotective layer constituting the gas-barrier film layer to belaminated, and more preferably, the adhesive layer is stuck to thesubstrate surface of the gas-barrier film layer to be laminated.

The gas-barrier film laminate of the present invention does not containat all bubbles and/or impurities having a diameter of the largest partthereof of at least 0.5 mm, or contains them in an amount by number ofat most 3 per 100 cm². The diameter of the bubbles or the impurities maybe measured according to a method of using a stereomicroscope.Impurities as referred to herein mean, for example, resin powder, metalpowder, etc. In case where the impurities take bubbles therein, then thesize of the bubble is measured as the diameter thereof.

In the present invention, the number or such bubbles and impurities isat most 3 per 100 cm² of the gas-barrier film laminate; but from theviewpoint of the appearance and the optical properties thereof, thenumber is preferably at most 2, more preferably at most 1, even morepreferably at most 0.1. In particular, in the present invention, in casewhere the laminate comprises at least three layers, the number of thebubbles and the impurities is preferably at most 2 per 100 cm² of thegas-barrier film laminate.

In the present invention, “between the gas-barrier films” where theabove-mentioned bubbles or impurities may exist is meant to indicate thetotal number of the bubbles and the impurities existing in the pluralinterlayers to be formed by the plural gas-barrier film layers.

In the present invention, for controlling the bubbles and/or theimpurities to fall within the above-mentioned range, various methods maybe employable with no specific limitation. Preferred are any of (a) amethod of using an epoxy-based resin or an acrylic resin as the adhesivelayer; (b) a method of heating the gas-barrier film layers orirradiating them with energy rays in a vacuum atmosphere at not morethan 1000 Pa, after or during laminating the gas-barrier film layers;(c) a method of heating the layers under a pressure not lower thanatmospheric pressure after temporarily pressing them in a vacuumatmosphere; (d) a method of adding organic fine particles or inorganicfine particles to the adhesive layer; (e) in addition to the abovemethods, a method of controlling the surface roughness (Rms) of theadhesive layer to a specific level, etc.

The methods (a), (d) and (e) are as mentioned in the above. In themethod (b) of lamination in a vacuum atmosphere, preferably, the heatingor the irradiation with energy rays is attained in a vacuum atmosphereat not more than 200 Pa for preventing the formation of bubbles betweenthe gas-barrier films, more preferably at not more than 20 Pa, even morepreferably at not more than 10 Pa.

In the methods (a) and (b), the heating is attained preferably at atemperature of from 30 to 250° C., more preferably from 50 to 200° C.,even more preferably from 80 to 180° C., from the viewpoint ofpreventing the formation of bubbles between the gas-barrier film layers.Preferably, the heating is attained under pressure, from the viewpointof the adhesiveness of the layers. The pressure is preferably from 1 to50 kgf/cm² in terms of the surface pressure; more preferably, thesurface pressure is from 5 to 25 kgf/cm², even more preferably from 10to 20 kgf/cm². The method for heating and pressure application is notspecifically defined. For example, the composition is put into a moldnot closed, and the metal plate in the mold is heated externally tothereby indirectly heat the composition. As the indirect heating method,for example, a heater is fitted to the outer surface of the metal plateto heat the composition, or a heating medium flow line is provided inthe metal plate and the composition is heated with steam, hot oil or thelike according to a jacket system. The mold is pressed under apredetermined pressure and then cooled to obtain a gas-barrier filmlaminate.

In the above-mentioned method (c) of temporary pressing in a vacuumatmosphere, preferably, the layers are pressed under the pressure in thevacuum condition of the above (a).

The energy rays include active energy rays such as visible light, UVrays, electron rays, radioactive rays, etc. Of those, preferred are UVrays and electron rays from the viewpoint of more efficiently preventingthe formation of bubbles between the gas-barrier film layers. In casewhere UV rays are radiated as active energy rays, various light emittingsources are usable with no specific limitation, such as typically UVlamps, e.g., low-pressure mercury lamp, high-pressure mercury lamp,xenon lamp, etc.; and the irradiation may be controlled in accordancewith the film thickness and the curing condition. The radiation energyof UV rays is preferably from 100 to 5000 mJ/cm², more preferably from1000 to 3000 mJ/cm². When the radiation energy is within the aboverange, resin layers may be sufficiently cured and it is favorable fromthe viewpoint of producibility.

The method of irradiation with electron rays as active energy rays forcuring is preferred, as not requiring a photoinitiator. The absorptiondose of electron rays is preferably within a range of from 1 to 200 kGywithin which resin layers can be fully cured, more preferably within arange of from 5 to 100 kGy within which the curing is more satisfactorycausing little damage to plastic films and resin layers. When theabsorption dose is within the above range, then resin layers may becured sufficiently with no damage to plastic films and resin layers, notdetracting from the gas-barrier property thereof.

In case where electron rays are radiated as active energy rays, anyknown apparatus can be used. In consideration of the damage caused byelectron rays to plastic films and resin layers, preferred isirradiation with electron rays having an acceleration voltage of from 1kV to 200 kV. When the acceleration voltage of the electron rays fallswithin the above range, then the curing depth is satisfactory and themechanical properties of the obtained substrates for gas-barrier filmlaminates are not worsened. Forming resin layers through irradiationwith electron rays having a low acceleration voltage of at most 100 kV,especially at most 50 kV is favorable, as not lowering the mechanicalstrength of the substrates for gas-barrier film laminates.

The gas-barrier film layer to form the gas-barrier film laminate of thepresent invention comprises a substrate film and at least oneconstitutive unit layer formed on the substrate film.

The substrate film is preferably a plastic film having a shrinkage at150° C. of from 0.01 to 5%, from the viewpoint of the barrier propertythereof, more preferably a plastic film having a shrinkage of 0.01 to2%. The shrinkage may be determined from the dimensional change beforeand after heating in a hot air oven.

Not specifically defined, the material for the substrate film may be anyand every resin usable for ordinary packaging materials. Concretely, itincludes various resins, for example, amorphous polyolefins, e.g.,polyolefins such as homopolymers or copolymers of ethylene, propylene,butene, etc., or cyclic polyolefins; polyesters such as polyethyleneterephthalate, polyethylene-2,6-naphthalate, etc.; polyamides such asnylon 6, nylon 66, nylon 12, copolymer nylon, etc.; polyvinyl alcohol,partially-hydrolyzed ethylene/vinyl acetate copolymer (EVOH), polyimide,polyetherimide, polysulfone, polyether sulfone, polyether ether ketone,polycarbonate, polymethacrylate, polyvinyl butyral, polyarylate,fluororesins, acrylate resins, biodegradable resins, etc. Of those,preferred are polyester resins, polycarbonate-based resins,polymethacrylic resins, polyetherimide-based resins, polyether sulfoneand cyclic olefin-based resins, from the viewpoint of the film strengthand the cost. The substrate film may contain known additives, forexample, antistatic agent, light-shielding agent, UV absorbent,plasticizer, lubricant, filler, colorant, stabilizer, release agent,crosslinking agent, antiblocking agent, antioxidant, etc.

The plastic film for the substrate film is formed by shaping theabove-mentioned material; and for use as a substrate, the film may beunstretched or stretched. It may be laminated with any other plasticsubstrate. The substrate film may be produced in any known method. Forexample, the starting resin is melted in an extruder, extruded outthrough a ring die or a T-die, and then rapidly cooled to produce asubstantially amorphous, non-oriented unstretched film. The unstretchedfilm may be stretched in the film flow (longitudinal) direction or inthe direction perpendicular (transversal) to the film flow direction,according to a known method of monoaxial stretching, tenter-assistedsuccessive biaxial stretching, tenter-assisted simultaneous biaxialstretching, tubular simultaneous biaxial stretching or the like, therebyproducing a film stretched in at least monoaxial direction. Thethickness of the substrate is selected generally within a range of from5 to 500 μm in accordance with the use thereof and from the viewpoint ofthe mechanical strength, the flexibility and the transparency of thesubstrate for the gas-barrier film laminate of the present invention,preferably within a range of from 10 to 200 μm. The substrate filmincludes thick sheets. Not specifically defined, the width and thelength of the film may be selected in any desired manner in accordancewith the use thereof.

The constitutive unit layer to constitute the gas-barrier film layercomprises an anchor coat layer and an inorganic thin film. The anchorcoat layer to constitute the constitutive unit layer may be a layer ofat least any one selected from a resin such as a thermosetting resin ora thermoplastic resin, as well as a metal, a metal oxide and a metalnitride.

The resin such as thermosetting resin or thermoplastic resin to form theanchor coat layer may be any solvent-base or water-base resin.Concretely, one or more of polyester-based resin, urethane-based resin,acrylic resin, nitrocellulose-based resin, silicone-based resin,alcoholic hydroxyl group-containing resin (vinyl alcohol-based resin,ethylene/vinyl alcohol-based resin, etc.), vinyl-based modified resin,isocyanate group-containing resin, carbodiimide-based resin, alkoxylgroup-containing resin, epoxy-based resin, oxazolin group-containingresin, modified styrene-based resin, modified silicone-based resin,alkyl titanate and the like may be used either singly or as combined.

In the present invention, at least one resin selected from a groupconsisting of polyester-based resin, urethane-based resin, acrylicresin, isocyanate group-containing resin, oxazoline group-containingresin, carbodiimide-based resin, alcoholic hydroxyl group-containingresin and copolymer of at least two resins of these is preferably usedfrom the viewpoint of the gas-barrier property thereof. Above all,preferred is polyester-based resin.

The polyester-based resin for use for the anchor coat layer may beprepared by reacting a polycarboxylic acid ingredient and polyalcoholingredient. The polycarboxylic acid ingredient includes terephthalicacid, isophthalic acid, adipic acid, sebacic acid, azelaic acid,orthophthalic acid, diphenylcarboxylic acid, dimethylphthalic acid,etc.; and the polyalcohol ingredient includes ethylene glycol,1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, diethyleneglycol, neopentyl glycol, dipropylene glycol, 1,6-hexanediol, bisphenolA, etc.

The molecular weight of the resin to constitute the anchor coat layermay be from 3,000 to 30,000 in terms of the number-average molecularweight thereof, from the viewpoint of the gas-barrier property and theadhesiveness of the layer, preferably from 4,000 to 28,000, morepreferably from 5,000 to 25,000.

From the viewpoint of enhancing the interlayer adhesiveness, asilane-coupling agent is preferably added to the anchor coat layer. Thesilane-coupling agent includes, for example, an epoxy group-containingsilane coupling agent such asβ-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,γ-glycidoxypropylmethyldiethoxysilane,γ-glycidoxypropyltrimethoxysilane; an amino group-containingsilane-coupling agent such as γ-aminopropyltrimethoxysilane,N-β-(aminoethyl)-γ-aminopropylmethyldiethoxysilane,N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane,N-β-(aminoethyl)-γ-aminopropyltriethoxysilane; and their mixtures. Fromthe viewpoint of the interlayer adhesiveness,γ-glycidoxypropyltrimethoxysilane and γ-aminopropyltrimethoxysilane arepreferred as the silane-coupling agent. One or more such silane-couplingagents may be used either singly or as combined. From the viewpoint ofthe adhesiveness of the layer, the silane-coupling agent is added to theanchor coat layer preferably in an amount of from 0.1 to 80% by massrelative to the resin that forms the layer, more preferably from 1 to50% by mass.

Preferably, a curing agent is added to the anchor coat layer. As thecuring agent, preferred is polyisocyanate. Concretely, for example, itincludes aliphatic polyisocyanates such as hexamethylene diisocyanate,dicyclohexylmethane diisocyanate; and aromatic polyisocyanates such asxylene diisocyanate, tolylene diisocyanate, diphenylmethanediisocyanate, polymethylene polyphenylene diisocyanate, tolylenediisocyanate, naphthalene diisocyanate, etc. Especially preferred arebifunctional or more polyfunctional polyisocyanates from the viewpointof enhancing the gas-barrier property of the layer.

If desired, various known additives may be added to the anchor coatlayer. The additives include polyalcohols such as glycerin, ethyleneglycol, polyethylene glycol, polypropylene glycol; water-base epoxyresin; lower alcohols such as methanol, ethanol, normal propanol,isopropanol; ethers such as ethylene glycol monomethyl ether, propyleneglycol monomethyl ether, propylene glycol diethyl ether, diethyleneglycol monoethyl ether, propylene glycol monoethyl ether; esters such aspropylene glycol monoacetate, ethylene glycol monoacetate; antioxidant,weather-resistant stabilizer, UV absorbent, antistatic agent, pigment,dye, microbicide, lubricant, inorganic filler, antiblocking agent,adhesive, etc.

As the metal to form the anchor coat layer, preferred are chromium,aluminium, silicon, nickel, titanium, tin, iron, molybdenum and alloysof two or more of these, from the viewpoint of the gas-barrier propertyand the adhesiveness of the layer. As the metal oxide and the metalnitride, preferred are oxides and nitrides of the above-mentioned metalfrom the viewpoint of the gas-barrier property and the adhesiveness. Inthe present invention, as the anchor coat layer, preferred is at leastone selected from chromium, silicon oxide, aluminium oxide, titaniumoxide, silicon nitride, aluminium nitride and titanium nitride, from theabove-mentioned viewpoint; and more preferred is at least one selectedfrom silicon oxide and silicon nitride. Also preferred for use as theanchor coat layer is a substance consisting essentially of a hydrocarbonsuch as diamond-like carbon.

In the gas-barrier film laminate of the present invention, the thicknessof the anchor coat layer may be from 0.1 to 5,000 nm, but preferablyfrom 0.1 to 2,000 nm, more preferably from 0.1 to 1,000 nm from theviewpoint of the adhesiveness of the layer. For enhancing thewaterproofness and the durability thereof, the anchor coat layer may becrosslinked through irradiation with energy rays.

For forming the anchor coat layer, employable is any known coatingmethod. For example, employable is any coating method with a reverseroll coater, a gravure coater, a rod coater, an air doctor coater, aspray or a brush. As the case may be, the substrate film and thevapor-deposited film may be dipped in a resin liquid for the formation.After coated, the solvent may be evaporated away in any known dryingmethod of heating such as hot air drying or hot roll drying at atemperature of from 80 to 200° C. or so, or IR drying. As a result, alaminate film having a uniform coating layer may be produced.

For forming the anchor coat layer comprising at least one selected froma metal, a metal oxide and a metal nitride, employable is any method of,for example, a vapor deposition method such as PVD (physical vapordeposition), e.g., vacuum evaporation deposition, ion plating orsputtering, or CVD (chemical vapor deposition), or a coating method.From the viewpoint of forming a uniform thin film having goodadhesiveness, a vapor deposition method is preferred. For the vapordeposition method, usable is the same method as that for use in formingan inorganic thin film to be mentioned hereunder.

For enhancing the coatability and adhesiveness of the anchor coat agentto the substrate film, the substrate film may be processed for ordinarysurface treatment such as chemical treatment or discharge treatmentbefore the anchor coat agent is applied to the substrate film.

In the constitutive unit layer to constitute the gas-barrier film layer,an inorganic thin film is formed on the anchor coat layer. The inorganicsubstance to constitute the inorganic thin film includes silicon,aluminium, magnesium, zinc, tin, nickel, titanium, hydrocarbons, etc.,and also their oxides, carbides, nitrides and their mixtures. Preferredare silicon oxide, silicon nitride, aluminium oxide, aluminium nitride,and substances consisting essentially of hydrocarbon such asdiamond-like carbon. More preferred are silicon oxide and aluminiumoxide, as capable of stably maintaining a high-level gas-barrierproperty. One or more of the above-mentioned inorganic substances may beused either singly or as combined.

For forming the inorganic thin film, employable is any method of a vapordeposition method or a coating method; but preferred is a vapordeposition method as capable of forming a uniform thin film having ahigh-level gas-barrier property. The vapor deposition method includesany methods of PVD (physical vapor deposition) such as vacuum vapordeposition, ion plating or sputtering, and CVD (chemical vapordeposition).

The thickness of the inorganic thin film may be generally from 0.1 to500 nm, but preferably from 0.5 to 40 nm. Within the above range, theinorganic thin film may have a sufficient gas-barrier property and isexcellent in transparency with no trouble of cracking or delamination ofthe inorganic thin film.

In the present invention, the gas-barrier film layer includes one havingan inorganic thin film between the substrate film and the constitutiveunit layer. The inorganic thin film may be the same as that constitutingthe constitutive unit layer mentioned in the above.

The gas-barrier film layer may have a protective layer as the outermostlayer thereof. The resin to form the protective layer may be any of asolvent-base or water-base resin. Concretely, one or more ofpolyester-based resin, urethane-based resin, acrylic resin, polyvinylalcohol-based resin, ethylene/unsaturated carboxylic acid copolymer,ethylene/vinyl alcohol-based resin, vinyl-modified resin,nitrocellulose-based resin, silicone-based resin, isocyanate-basedresin, epoxy-based resin, oxazoline group-containing resin, modifiedstyrene-based resin, modified silicone-based resin, alkyl titanate andthe like may be used either singly or as combined. As the protectivelayer, usable is a layer formed of a mixture prepared by mixing at leastone type of inorganic particles selected from silica sol, alumina sol,particulate inorganic filler and layered inorganic filler, with at leastone resin as above for enhancing the barrier property, the abrasionresistance and the lubricity of the layer, or a layer comprising aninorganic particles-containing resin formed through polymerization ofthe above-mentioned resin material in the presence of the inorganicparticles.

As the resin to form the protective layer, preferred is theabove-mentioned water-base resin from the viewpoint of enhancing thegas-barrier property of the inorganic thin film. As the water-baseresin, more preferred is vinyl alcohol resin or ethylene/vinyl alcoholresin. As the protective layer, usable is a resin layer formed bycoating with a water-base liquid that contains polyvinyl alcohol andethylene/unsaturated carboxylic acid copolymer.

The thickness of the protective layer is preferably from 0.05 to 10 μm,more preferably from 0.1 to 3 μm from the viewpoint of the printabilityand the workability thereof. For forming the layer, employable is anyknown coating method. For example, employable is any coating method witha reverse roll coater, a gravure coater, a rod coater, an air doctorcoater, a spray or a brush. As the case may be, the vapor-deposited filmmay be dipped in a resin liquid for protective layer. After coated,water may be evaporated away in any known drying method of heating suchas hot air drying or hot roll drying at a temperature of from 80 to 200°C. or so, or IR drying. As a result, a film having a uniform coatinglayer may be produced.

In the present invention, the number of the constitutive unit layer toform the gas-barrier film layer is at least one, but from the viewpointof the gas-barrier property thereof, the number of the layers ispreferably from 1 to 10, more preferably from 1 to 5. In case where thegas-barrier film layer has the plural constitutive unit layers, then theconstitutive unit layers may be the same or different. Regarding thenumber of the constitutive unit layers as referred to herein, oneconstitutive unit that comprises an anchor coat layer and an inorganicthin film is one layer of the constitutive unit layer.

Preferred embodiments of the gas-barrier film layer to constitute thegas-barrier film laminate are mentioned below.

(1) Substrate film/AC/inorganic thin film,

(2) Substrate film/AC/inorganic thin film/AC/inorganic thin film,

(3) Substrate film/AC/inorganic thin film/AC/inorganic thinfilm/Ac/inorganic thin film,

(4) Substrate film/AC/inorganic thin film/AC/inorganic thinfilm/AC/inorganic thin film/AC/inorganic thin film,

(5) Substrate film/AC/inorganic thin film/protective layer,

(6) Substrate film/AC/inorganic thin film/AC/inorganic thinfilm/protective layer,

(7) Substrate film/AC/inorganic thin film/AC/inorganic thinfilm/AC/inorganic thin film/protective layer,

(8) Substrate film/AC/inorganic thin film/AC/inorganic thinfilm/AC/inorganic thin film/AC/inorganic thin film/protective layer,

(9) Substrate film/inorganic thin film/AC/inorganic thin film,

(10) Substrate film/inorganic thin film/AC/inorganic thinfilm/AC/inorganic thin film,

(11) Substrate film/inorganic thin film/AC/inorganic thinfilm/AC/inorganic thin film/AC/inorganic thin film,

(12) Substrate film/inorganic thin film/AC/inorganic thinfilm/protective layer,

(13) Substrate film/inorganic thin film/AC/inorganic thinfilm/AC/inorganic thin film/protective layer,

(14) Substrate film/inorganic thin film/AC/inorganic thinfilm/AC/inorganic thin film/AC/inorganic thin film/protective layer.

(Ac means an anchor coat layer).

The water vapor permeability (moisture permeability) through thegas-barrier film layer at 40° C. and 90% RH is preferably at most 0.2g/m²/24 hr from the viewpoint of the barrier property as a result oflamination, more preferably at most 0.1 g/m²/24 hr, even more preferablyat most 0.05 g/m²/24 hr.

The gas-barrier film laminate of the present invention has at least twogas-barrier film layers each comprising at a substrate film and at leastone constitutive unit layer, preferably having from 2 to 100, morepreferably from 3 to 20, even more preferably from 3 to 10 of suchgas-barrier film layers from the viewpoint of the gas-barrier propertyand the producibility thereof. The plural gas-barrier film layers may bethe same or different. Regarding the number of the gas-barrier filmlayers as referred to herein, one gas-barrier film layer that comprisesa substrate film and at least one constitutive unit layer is one layerof the gas-barrier film layer.

In the present invention, usable are various gas-barrier film laminatesoptionally laminated with any other additional constitutive layers inaccordance with the use thereof. In practical embodiments, gas-barrierfilms having an additional plastic film on the inorganic thin film orthe protective film mentioned in the above can be used in variousapplications. The thickness of the plastic film may be selected inaccordance with the use thereof, from a range of generally from 5 to 500μm, preferably from 10 to 200 μm, from the viewpoint of the mechanicalstrength, the flexibility and the transparency thereof as the substrateof the laminates. Not specifically defined, the width and the length ofthe film may be suitably selected in accordance with the use thereof.For example, a heat-sealable resin may be used on the inorganic thinfilm or the protective layer, and the laminate of the type may beheat-sealable and may be used as various containers. The heat-sealableresin may be any known resin including, for example, polyethylene resin,polypropylene resin, ethylene/vinyl acetate copolymer, ionomer resin,acrylic resin, biodegradable resin, etc.

As other embodiments of the gas-barrier film laminate than thosedescribed in the above, there may be mentioned one having a print layerformed on the coating surface of the inorganic thin film or theprotective layer, and further having a heat-sealable rein laminatedthereon. As the printing ink to form the print layer, usable is awater-base or solvent-base resin-containing printing ink. The resin foruse in the printing ink includes acrylic resin, urethane-based resin,polyester-based resin, vinyl chloride-based resin, vinyl acetatecopolymer resin and their mixtures. Further, any known additives may beadded to the printing ink, such as antistatic agent, light-shieldingagent, UV absorbent, plasticizer, lubricant, filler, colorant,stabilizer, release agent, defoaming agent, crosslinking agent,antiblocking agent, antioxidant, etc.

The printing method for providing the print layer is not specificallydefined. For example, employable is any known printing method of offsetprinting, gravure printing, screen printing, etc. For drying the solventafter printing, employable is any known drying method of hot air drying,hot roll drying, IR drying, etc. At least one layer of paper or plasticfilm may be put between the print layer and the heat-sealable layer. Asthe plastic film, usable is the same thermoplastic polymer film as thatfor the substrate film for the gas-barrier film laminate of the presentinvention. Above all, from the viewpoint of attaining sufficientrigidity and strength of the laminate, preferred is paper, polyesterresin, polyamide resin or biodegradable resin.

In the present invention, preferably, after the anchor coat layer or theinorganic thin film of the gas-barrier film layer has been formed andthen a protective layer has been formed, or after the gas-barrier filmlaminate has been formed, it is processed for heat treatment from theviewpoint of the gas-barrier property, stabilizing the quality of thefilm and the quality of the coating layer and finely dispersing thebubbles. The condition of the heat treatment may vary depending on thetype and the thickness of the components constituting the gas-barrierfilm layer. Not specifically defined, any method capable of maintainingthe necessary temperature and time may be employable for the treatment.For example, employable are a method of storing the laminate in an ovenor a thermostat chamber set at a necessary temperature; a method ofjetting hot air to it; a method of heating it with an IR heater; amethod of irradiating it with light from a lamp; a method of contactingit with a hot roll or a hot plate to directly impart heat thereto; and amethod of irradiating it with microwaves. If desired, the film may becut into sheets having a size of easy handlability and thenheat-treated, or the roll film may be directly heat-treated. Inaddition, so far as the method ensures the necessary time andtemperature, a heating unit may be built in a part of the filmproduction apparatus such as a coater or a slitter, and the film may beheated with it during its production.

Not specifically defined, the temperature in the heat treatment may beany one lower than the melting point of the substrate and the plasticfilm used. Preferably, the heating temperature is not lower than 60° C.,more preferably not lower than 70° C., at which the necessary processingtime for attaining the effect of the heat treatment is easy to set. Theuppermost limit of the heat-treatment temperature may be generally 200°C., preferably 160° C. from the viewpoint of preventing the degradationof the gas-barrier property of the gas-barrier film laminate owing tothermal decomposition of the constitutive components of the laminate.The treatment time depends on the heat-treatment temperature, and ispreferably shorter when the treatment temperature is higher. Forexample, when the heat treatment temperature is 60° C., the treatmenttime may be from days to 6 months or so; when the temperature is 80° C.,the treatment time may be from 3 hours to 10 days or so; when thetemperature is 120° C., the treatment time may be from 1 hour to day orso; and when the temperature is 150° C., the treatment time may be from3 to 60 minutes or so. However, these are only tentative standards, andmay be suitably changed or controlled depending on the type and thethickness of the constitutive components of the gas-barrier filmlaminate.

The gas-barrier film laminate of the present invention preferably has awater vapor permeability (moisture permeability) at 40° C. and 90% RH ofat most 0.02 g/m²/24 hr, more preferably at most 0.01 g/m²/24 hr, evenmore preferably at most 0.005 g/m²/24 hr, from the viewpoint of securingcontents.

Also preferably, the gas-barrier film laminate has a total lighttransmittance of at least 70%, more preferably at least 75%, even morepreferably at least 80%, from the viewpoint of the optical propertiesthereof.

Method for Producing Gas-Barrier Film Laminate

A method for producing the gas-barrier film laminate of the presentinvention comprises (a) a step of forming, on a substrate, at least oneconstitutive unit layer comprising an anchor coat layer and an inorganicthin film layer in that order, thereby forming a gas-barrier film layer,and (b) a step of laminating at least two formed gas-barrier film layersvia an adhesive layer of an epoxy-based resin. Another method forproducing the gas-barrier film laminate of the present inventioncomprises (a) a step of forming, on a substrate, at least oneconstitutive unit layer comprising an anchor coat layer and an inorganicthin film layer in that order, thereby forming a gas-barrier film layer,(b) a step of laminating at least two formed gas-barrier film layers viaan adhesive layer, and (c) after or simultaneously with the laminationof gas-barrier film layers, a step of heating it or irradiating it withenergy rays in a vacuum atmosphere at not more than 1000 Pa.

The gas-barrier film layer, the anchor coat layer and the inorganic thinfilm layer to constitute it, the gas-barrier film laminate formed bylaminating at least two gas-barrier film layers, and the adhesive layerare as described hereinabove. The heating and irradiation with energyrays in a vacuum atmosphere is also as described hereinabove.

EXAMPLES

The present invention is described further concretely with reference toExamples, by which, however, the present invention should not berestricted at all. The properties of the gas-barrier film laminatesobtained in Examples were evaluated in the manner mentioned below.

(1) Water Vapor Permeability (Moisture Permeability):

The water vapor permeability was measured by the following procedureaccording to the conditions prescribed in JIS Z 0222 “Method for TestingWater Vapor Permeability of Moisture-Proof Packaging Containers” and JISZ 0208 “Method for Testing Water Vapor Permeability of Moisture-ProofPackaging Materials (Cup Method)”. Two gas-barrier film laminates orgas-barrier film layers each having a water vapor-permeable area of 10.0cm×10.0 cm were formed into a bag sealed along four sides thereofenclosing about 20 g of anhydrous calcium chloride as a moistureabsorbent. The thus prepared bag was placed in a thermo-hygrostatchamber maintained at a temperature of 40° C. and a relative humidity of90%, and a mass (unit: 0.1 mg) of the bag was measured at time intervalsof 48 hours or longer until 14 days elapsed at which the increase inmass of the bag was kept substantially constant, and the water vaporpermeability of the bag was computed from the following formula. Thewater vapor permeability values on the day 14 are shown in Table 1.Water Vapor Permeability (g/m²/24 h)=(m/s)/twherein m is an increase in mass (g) of the bag occurring during thelast two time intervals for the measurement among the testing period;s is a water vapor-permeable area (m²); andt represents the value expressed by [(time (h) taken during the last twotime intervals for the measurement among the testing period)/24 (h)].(2) Oxygen Permeability of Adhesive Layer:

An adhesive was applied to a biaxially-stretched polypropylene (OPP)film having an oxygen permeability of 30000 ml/m²/24 hr/MPa and a watervapor permeability of 8 g/m²/24 hr and having a thickness of 20 μm, tobe a predetermined thickness. Using MOCON's OX-TRAN 2/21, the oxygenpermeability at 25° C. and 90% RH of the adhesive-coated OPP film wasmeasured, and the oxygen permeability of the adhesive layer wascomputed.

(3) The Number of Bubbles Having a Diameter of at Least 0.5 Mm, ExistingBetween Gas-Barrier Film Layers:

The diameter of bubbles was measured with a stereomicroscope. The numberof bubbles was visually counted and converted into that per 100 cm² ofthe sample. The data were averaged with n=3, and based on thethus-computed number of bubbles, the samples were evaluated according tothe following 5 ranks.

◯◯: The number of bubbles was not more than 1/100 cm².

◯: The number of bubbles was not more than 2/100 cm².

Δ: The number of bubbles was not more than 3/100 cm².

x: The number of bubbles was from 4 to less than 20/100 cm².

xx: The number of bubbles was 20/100 cm² or more.

(4) Interlayer Adhesion Strength:

According to JIS Z1707, the film laminate was cut into a narrowrectangular piece having a width of 15 mm, and its one edge was partlypeeled. Using a peeling tester (Shimadzu's trade name, EZ-TEST), thiswas T-peeled at a speed of 300 mm/min to measure the lamination strength(g/15 mm).

(5) Vacuum Sealing:

A dry-laminated substrate was prepared, having a constitution ofpolyethylene terephthalate resin (hereinafter abbreviated as“PET”—Mitsubishi Chemical's Novapex having a thickness of 12μm)/unstretched polypropylene film (Toyobo's Pylen Film-CT P1146 havinga thickness of 100 μm); and two sheets of 30 cm×30 cm were cut out ofit. These were put one upon another with their CPP sides kept facingeach other, and the three sides were heat-sealed with an impulse sealerto produce a bag for vacuum packaging. The gas-barrier film laminate wasput into the thus-produced bag and sealed up in vacuum at 10 Pa or lessfor vacuum sealing.

(6) Measurement of Surface Roughness (Rms):

Using a non-contact mode (dynamic force mode) scanning probe microscope(Seiko Instruments' SPI3800), the surface of the gas-barrier film layerwas analyzed. Regarding the scanning speed, the number of test points inone test region and the correction for grade, the parameters with whichthe surface condition could be clearly determined were selected. Thesurface roughness (Rms) of the surface condition of the film wasdetermined through AERA analysis with a software program of “CROSSSECTION” attached to the scanning probe microscope SPI3800.

(7) Total Light Transmittance:

Using a haze meter (Nippon Denshoku Kogyo's HDH2000), the total lighttransmittance of the film was determined according to a lighttransmittance method.

Example 1

PET (Mitsubishi Chemical's Novapex) was melt-extruded into a sheet,which was then stretched in the machine direction at a stretchingtemperature of 95° C. and in a draw ratio of 3.3, then stretched in thetransverse direction at a stretching temperature of 110° C. and in adraw ratio of 3.3, and then heat-fixed at 230° C., thereby producing abiaxially stretched PET film of which the shrinkage at 150° C. in MD(machine direction) was 1.2% and the shrinkage in TD (transversedirection, direction perpendicular to the machine direction) was 0.5%.On one surface of the film, formed was an anchor coat layer having athickness of 0.1 μm by applying thereto a 1/1 (by mass) mixture of anisocyanate compound (Nippon Polyurethane Industry's Coronate L and asaturated polyester (Toyobo's Vylon 300) and drying it according to agravure coating method.

Next, using a vacuum vapor deposition apparatus, SiO was vaporizedaccording to a high-frequency heating system in a vacuum of 1×10⁻⁵ Torr,thereby forming an inorganic thin film having a thickness of about 20 nmon the anchor coat layer.

Onto the inorganic thin film of the gas-barrier film layer, applied wasan aqueous ionomer resin dispersion (Mitsui Chemical's Chemipearl S300)to which were added silica particles having a mean particle size of 1 μmin an amount of 10% by mass relative to the resin solid, thereby forminga thermosetting adhesive layer having a dry thickness of about 3 μm anda surface roughness (Rms) of 0.20 μm. The gas-barrier film with theadhesive layer formed was cut into pieces of 12 cm×12 cm each. Fivethose gas-barrier film pieces were put one upon another in such a mannerthat the adhesive layer could face the PET surface of the substrate; andthe outermost adhesive layer was stuck to an unstretched polypropylenefilm (Toyobo's Pylen Film-CT P1146) having a size of 12 cm×12 cm and athickness of 60 μm; and according to the above-mentioned method, thiswas packaged in vacuum. The thus vacuum-packaged gas-barrier filmlaminate was heated in an oven under atmospheric pressure at 120° C. for30 minutes whereby the adhesive layer was melted to be adhesive toproduce a gas-barrier film laminate. The obtained gas-barrier filmlaminate was evaluated as above. The results are shown in Table 1.

Example 2

A gas-barrier film laminate was produced in the same manner as inExample 1, for which, however, a polyethylene naphthalate film(hereinafter abbreviated as “PEN”—Teijin's Teonex Q65 having a thicknessof 75 μm) was used as the substrate of the gas-barrier film layer. Theobtained gas-barrier film laminate was evaluated as above. The resultsare shown in Table 1.

Example 3

A gas-barrier film laminate was produced in the same manner as inExample 1, for which, however, a polyether imide film (hereinafterabbreviated as “PEI”—Mitsubishi Plastics' Superio UT having a thicknessof 10 μm) was used as the substrate of the gas-barrier film layer. Theobtained gas-barrier film laminate was evaluated as above. The resultsare shown in Table 1.

Example 4

A gas-barrier film laminate was produced in the same manner as inExample 1, in which, however, the number of the gas-barrier film layerslaminated was 9. The obtained gas-barrier film laminate was evaluated asabove. The results are shown in Table 1.

Example 5

A gas-barrier film laminate was produced in the same manner as inExample 1, in which, however, the anchor coat layer of the gas-barrierfilm layer was a silicon nitride/silicon oxide composite film SiON layer(silicon nitride/silicon oxide=8/2) having a thickness of 10 nm, asformed through deposition according to a plasma CVD method wherestarting gases of monosilane, oxygen, ammonia and hydrogen were fed withapplying a predetermined power thereto in vacuum by degassing, and inwhich the number of the gas-barrier film layers laminated was 9. Theobtained gas-barrier film laminate was evaluated as above. The resultsare shown in Table 1.

Example 6

A gas-barrier film laminate was produced in the same manner as inExample 1, in which, however, the anchor coat layer of the gas-barrierfilm layer was formed of chromium having a thickness of 0.1 nm throughsputtering in an argon atmosphere at 1 Pa in a DC magnetron sputteringapparatus using chromium as a target. The obtained gas-barrier filmlaminate was evaluated as above. The results are shown in Table 1.

Example 7

A gas-barrier film laminate was produced in the same manner as inExample 1, in which, however, the anchor coat layer of the gas-barrierfilm layer was formed of a 4/3/3 (by mass) mixture of urethane-basedresin, acrylic resin and oxazoline-based resin mentioned below. Theobtained gas-barrier film laminate was evaluated as above. The resultsare shown in Table 1.

Example 8

A gas-barrier film laminate was produced in the same manner as inExample 1, in which, however, the anchor coat layer of the gas-barrierfilm layer was formed of a 4/3/3 (by mass) mixture of urethane-basedresin, acrylic resin and carbodiimide-based resin mentioned below. Theobtained gas-barrier film laminate was evaluated as above. The resultsare shown in Table 1.

In Examples 7 and 8, the urethane-based resin, the acrylic resin, theoxazoline-based resin and the carbodiimide-based resin used for formingthe anchor coat layer are shown below.

<Urethane-Based Resin>

A polyester polyol was prepared, comprising terephthalic acid (664parts), isophthalic acid (631 parts), 1,4-butanediol (472 parts) andneopentyl glycol (447 parts). Next, adipic acid (321 parts) anddimethylolpropionic acid (268 parts) were added to the preparedpolyester polyol, thereby producing a pendant carboxyl group-containingpolyester polyol A. Further, hexamethylene diisocyanate (160 parts) wasadded to the polyester polyol A (1880 parts) to produce a water-basecoating material of polyurethane-based resin.

<Acrylic Resin>

A mixture of ethyl acrylate (40 parts by weight), methyl methacrylate(30 parts by weight), methacrylic acid (20 parts by weight) and glycidylmethacrylate (10 parts by weight) was solution-polymerized in ethylalcohol, and after the polymerization, this was heated with adding waterthereto to remove ethyl alcohol. This was conditioned at a pH of 7.5with aqueous ammonia added thereto, thereby producing a water-basecoating material of acrylic resin.

<Oxazoline-Based Resin>

Deionized water (179 parts) and a polymerization initiator2,2′-azobis(2-amidinopropane) dihydrochloride (1 part) were fed into aflask equipped with a stirrer, a reflux condenser, anitrogen-introducing duct, a thermometer and a dropping funnel, andheated at 60° C. with gradually introducing nitrogen gas thereinto. Amonomer mixture of ethyl acrylate parts), methyl methacrylate (2 parts)and 2-isopropenyl-2-oxazoline (16 parts) that had been previouslyprepared was dropwise added to it through the dropping funnel, taking 1hour. Next, this was reacted in a nitrogen current at 60° C. for 10hours. After the reaction, this was cooled to give a water-base liquidof 2-oxazoline group-containing resin having a solid concentration of10% by weight.

<Carbodiimide-Based Resin>

Hexamethylene diisocyanate (130 parts) and polyethylene glycolmonomethyl ether (mean molecular weight 400) (170 parts) were put into aflask equipped with a stirrer, a reflux condenser, anitrogen-introducing duct, a thermometer and a dropping funnel, andstirred at 120° C. for 1 hour. Further, 4,4′-dicyclohexylmethanediisocyanate (20 parts) and a carbodiimidation catalyst,3-methyl-1-phenyl-2-phosphorene-1-oxide (3 parts) were added to it, andfurther stirred in a nitrogen current at 185° C. for 5 hours. After thereaction, this was left cooled to 60° C., and distilled water was addedthereto to give a water-base liquid of carbodiimide-based crosslinkingagent having a solid concentration of 40% by weight.

Example 9

A gas-barrier film laminate was produced in the same manner as inExample 1, for which, however, the anchor coat layer as in Example 1 wasformed on the surface of the inorganic thin film of the gas-barrier filmlayer formed in Example 1, and then the inorganic thin film layer as inExample 1 was formed thereon. The obtained gas-barrier film laminate wasevaluated as above. The results are shown in Table 1.

Example 10

In the same manner as in Example 1, a gas-barrier film laminate wasvacuum-packaged, in which, however, the adhesive layer was formed of acoating liquid prepared by mixing and dissolving as an urethane(meth)acrylate ingredient, urethane acrylate (50 parts by mass), as anepoxy (meth)acrylate ingredient, bisphenol A glycidyl ether-type epoxyacylate (weight-average molecular weight, 2000) (20 parts by mass), asan alicyclic (meth)acrylate ingredient, tricyclodecane diacrylate (30parts by mass), and as a polymerization initiator,2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one(2 parts by mass). The UV-curable adhesive layer had a dry thickness ofabout 3 μm and a surface roughness (Rms) of 0.20 μm. The vacuum-packagedgas-barrier film laminate was irradiated with UV rays from a metalhalide lamp (80 W/cm) (Ushio Electric's UVC-05016S1AGF01) to cure theadhesive layer. The obtained gas-barrier film laminate was evaluated asabove. The results are shown in Table 1.

Example 11

A gas-barrier film laminate was produced in the same manner as inExample 10, in which, however, the number of the gas-barrier film layerslaminated was 9. The obtained gas-barrier film laminate was evaluated asabove. The results are shown in Table 1.

Example 12

A gas-barrier film laminate was produced in the same manner as inExample 10, in which, however, the anchor coat layer of the gas-barrierfilm layer was a silicon nitride/silicon oxide composite film SiON layer(silicon nitride/silicon oxide=8/2) having a thickness of 10 nm, asformed through deposition according to a plasma CVD method wherestarting gases of monosilane, oxygen, ammonia and hydrogen were fed withapplying a predetermined power thereto in vacuum by degassing, and inwhich the number of the gas-barrier film layers laminated was 9. Theobtained gas-barrier film laminate was evaluated as above. The resultsare shown in Table 1.

Example 13

A gas-barrier film laminate was vacuum-packaged in the same manner as inExample 1 but excepting the following: As the adhesive layer, used wasan adhesive film produced as follows: A composition comprising bisphenolA-type epoxy resin (weight-average molecular weight, 400; epoxyequivalent, 200; Yuka Shell Epoxy's Epikote 828) (30 parts by mass);bisphenol A novolak resin (weight-average molecular weight, 960;phenolic hydroxyl group equivalent, 120; Dai-Nippon Ink ChemicalIndustry's Phenolite LF2882) (25 parts by mass); as a polymer ingredientmiscible with epoxy resin, phenoxy resin (weight-average molecularweight, 50,000; Tohto Kasei's Phenotohto YP-50) (30 parts by mass); as apolymer ingredient immiscible with epoxy resin, epoxy group-containingacrylic rubber (weight-average molecular weight, 1,000,000; epoxyequivalent, 3,100; Teikoku Chemical Industry's HTR-860P-3) (30 parts bymass); as a curing promoter, 1-cyanoethyl-2-phenylimidazole (ShikokuChemical Industry's 2PZ-CN) (0.5 parts by mass); as a coupling agent,γ-glycidoxypropyltrimethoxysilane (Nippon Unicar's NUCA-187) (0.5 partsby mass); and as an inorganic ion adsorbent, antimony-bismuth-basedcompound (Toa Gosei Kagaku Kogyo's IXE600) (2 parts by mass) wasprepared; methyl ethyl ketone (150 parts by mass) was added to it, andmixed in a bead mill; and methyl ethyl ketone (30 parts by mass) wasfurther added thereto to control the viscosity of the resulting mixture,which was then degassed in vacuum.

The obtained varnish was applied onto a release PET film having athickness of 50 μm and a surface roughness Rms of 0.10 μm, using a knifecoater, and then heated at 110° C. for 15 minutes to remove the solventand to semi-cure the resin, thereby producing a release PETfilm-attached adhesive film in which the thickness of the adhesive layerwas 10 μm. The release PET film was peeled and removed from the releasePET film-attached adhesive film, thereby producing an adhesive filmhaving a thickness of 10 μm and a surface roughness (Rms) of 0.10 μm.Using the thus-obtained adhesive film, a vacuum-packaged gas-barrierfilm laminate was produced in the same manner as in Example 1, in which,however, the number of the gas-barrier film layers laminated was 9; andthe vacuum-packaged gas-barrier film laminate was heated in an ovenunder atmospheric pressure at 120° C. for 30 minutes whereby theadhesive layer was melted to be adhesive to produce a gas-barrier filmlaminate. The obtained gas-barrier film laminate was evaluated as above.The results are shown in Table 1.

Example 14

A gas-barrier film laminate was produced in the same manner as inExample 13, in which, however, the adhesive film prepared in Example 13was embossed with an embossing roll to thereby make both surfacesthereof have a surface roughness (Rms) of 5 μm. The obtained gas-barrierfilm laminate was evaluated as above. The results are shown in Table 1.

Example 15

An epoxy-based adhesive mentioned below was applied onto the surface ofthe inorganic thin film of the gas-barrier film layer formed in Example1, thereby forming a thermosetting adhesive layer thereon having a drythickness of about 3 μm and a surface roughness (Rms) of 0.25 μm, andthis was laminated with other gas-barrier film on the PET surfacethereof. Further, the same adhesive was applied in the same manner ontothe surface of the inorganic thin film of the thus-obtained gas-barrierfilm, and the outermost adhesive layer was laminated with an unstretchedpolypropylene film (Toyobo's Pylen Film-CT P1146) having a thickness of60 μm to produce a gas-barrier film laminate. The obtained gas-barrierfilm laminate was evaluated as above. The results are shown in Table 1.

<Epoxy-Based Adhesive>

This is an epoxy-based adhesive produced by preparing a methanol/ethylacetate (9/1) solution that contains epoxy resin having a glycidylaminemoiety derived from metaxylylenediamine (Mitsubishi Gas Chemical'sTETRAD-X) (50 parts by weight) and epoxy resin curing agent (a) (146parts by weight) (solid concentration; 35% by weight), followed byadding acrylic wetting agent (BYK's BYK381) (0.4 parts by weight) andsilicone-based defoaming agent (Kusumoto Chemical's Disparlon 1930N)(0.05 parts by weight) thereto.

<Epoxy Resin Curing Agent (a)>

Metaxylylenediamine (1 mol) was fed into a reactor. This was heated upto 60° C. in a nitrogen current, and methyl acrylate (0.93 mol) wasdropwise added thereto, taking 1 hour. After the addition, this wasstirred at 120° C. for 1 hour, and further heated up to 160° C. withremoving the formed methanol through evaporation, taking 3 hours. Thiswas cooled to 100° C., and a predetermined amount of methanol was addedthereto to make it have a solid concentration of 70% by weight, therebyproducing an epoxy resin curing agent (a).

Example 16

A gas-barrier film laminate was produced in the same manner as inExample 15, in which, however, the gas-barrier film layer used inExample 15 was changed to the gas-barrier film used in Example 2. Theobtained gas-barrier film laminate was evaluated as above. The resultsare shown in Table 1.

Example 17

A gas-barrier film laminate was produced in the same manner as inExample 16, in which, however, an adhesive layer was provided on thesurface of the inorganic thin film of the laminated other gas-barrierfilm layer in the same manner as in Example 16, and the same gas-barrierfilm layer was further provided thereon to be a 3-layered structure. Theobtained gas-barrier film laminate was evaluated as above. The resultsare shown in Table 1.

Example 18

A gas-barrier film laminate was produced in the same manner as inExample 15, in which, however, silica particles (Snowtec MEK-ST, byNissan Chemical Industries) having a mean particle size of 0.01 μm wereadded to the epoxy-based adhesive layer in an amount of 5% by massrelative to the resin solid content therein. The obtained gas-barrierfilm laminate was evaluated as above. The results are shown in Table 1.

Example 19

A gas-barrier film laminate was produced in the same manner as inExample 15, in which, however, polymer particles (Staphyloid AC3364, byGanz Chemical) having a mean particle size of 0.1 μm were added to theepoxy-based adhesive in an amount of 10% by mass relative to the resinsolid content therein. The obtained gas-barrier film laminate wasevaluated as above. The results are shown in Table 1.

Comparative Example 1

A gas-barrier film laminate was produced in the same manner as inExample 1, in which, however, the gas-barrier film layers were laminatedunder atmospheric pressure, not vacuum-packaged. The obtainedgas-barrier film laminate was evaluated as above. The results are shownin Table 1.

Comparative Example 2

A gas-barrier film laminate was produced in the same manner as inExample 10, in which, however, the gas-barrier films were laminatedunder atmospheric pressure, not vacuum-packaged. The obtainedgas-barrier film laminate was evaluated as above. The results are shownin Table 1.

Comparative Example 2

A gas-barrier film laminate was produced in the same manner as inExample 15, in which, however, the adhesive was changed to anurethane-based adhesive (mixture of Toyo Morton's and CAT-RT85 in aratio of 10/1.5). The obtained gas-barrier film laminate was evaluatedas above. The results are shown in Table 1.

TABLE 1 Moisture Surface Permeability through Roughness of OxygenPermeability Constitution of Gas-Barrier Film Layer Type of AdhesiveLayer/ Adhesive Layer through Adhesive Layer Gas-Barrier Film Layer[g/m² · 24 hr] Curing Method [μm] [ml/m²/24 hr/MPa] Example 1PET/AC/SiOx *1 0.2 adhesive coated/thermal curing 0.20 >1000 Example 2PEN/AC/SiOx *1 0.1 adhesive coated/thermal curing 0.20 >1000 Example 3PEI/AC/SiOx *1 0.07 adhesive coated/thermal curing 0.20 >1000 Example 4PET/AC/SiOx *1 0.2 adhesive coated/thermal curing 0.20 >1000 Example 5PET/AC/SiOx *2 0.05 adhesive coated/thermal curing 0.20 >1000 Example 6PET/AC/SiOx *3 0.2 adhesive coated/thermal curing 0.20 >1000 Example 7PET/AC/SiOx *1 0.2 adhesive coated/thermal curing 0.20 >1000 Example 8PET/AC/SiOx *1 0.1 adhesive coated/thermal curing 0.20 >1000 Example 9PET/AC/SiOx/AC/SiOx *1 0.03 adhesive coated/thermal curing 0.20 >1000Example 10 PET/AC/SiOx *1 0.2 adhesive coated/UV curing *4 0.10 500Example 11 PET/AC/SiOx *1 0.2 adhesive coated/UV curing *4 0.10 500Example 12 PET/AC/SiOx *2 0.05 adhesive coated/UV curing *4 0.10 500Example 13 PET/AC/SiOx *1 0.2 adhesive film/thermal curing 0.20 300Example 14 PET/AC/SiOx 0.2 adhesive film/thermal curing 5.00 300 Example15 PET/AC/SiOx *1 0.2 adhesive coated/thermal curing 0.25 80 Example 16PEN/AC/SiOx *1 0.1 adhesive coated/thermal curing 0.25 80 Example 17PEN/AC/SiOx *1 0.1 adhesive coated/thermal curing 0.25 80 Example 18PET/AC/SiOx *1 0.2 adhesive coated/thermal curing 0.27 80 Example 19PET/AC/SiOx *1 0.2 adhesive coated/thermal curing 0.35 80 ComparativePET/AC/SiOx *1 0.2 adhesive coated/thermal curing 0.20 >1000 Example 1Comparative PET/AC/SiOx *1 0.2 adhesive coated/UV curing *4 0.20 500Example 2 Comparative PET/AC/SiOx *1 0.2 adhesive coated/thermal curing0.20 >1000 Example 3 Number of Vacuum Degree in Moisture Number ofLaminated Lamination of Gas- Permeability Bubbles between Adhesion TotalLight Gas-Barrier Barrier Film Layers through Laminate Film LayersStrength Transmittance Film Layers [Pa] [g/m² · 24 hr] [/100 cm²] [g/15mm] [%] Example 1 5 10 0.02 ∘∘ 560 81 Example 2 5 10 0.01 ∘∘ 370 83Example 3 5 10 <0.01 ∘∘ 520 82 Example 4 9 10 <0.01 ∘ 520 77 Example 5 910 <0.01 ∘ 570 75 Example 6 9 10 <0.01 ∘ 560 72 Example 7 9 10 <0.01 ∘570 75 Example 8 9 10 <0.01 ∘ 550 75 Example 9 9 10 <0.01 ∘ 540 72Example 10 5 10 0.01 ∘∘ 510 82 Example 11 9 10 <0.01 ∘ 540 78 Example 129 10 <0.01 ∘ 560 75 Example 13 9 10 <0.01 ∘ 550 75 Example 14 9 10 <0.01∘∘ 520 77 Example 15 2 101325 0.03 ∘ 350 85 Example 16 2 101325 0.01 ∘370 86 Example 17 3 101325 <0.01 ∘ 370 84 Example 18 2 101325 0.03 ∘∘350 85 Example 19 2 101325 0.04 ∘∘ 360 85 Comparative 5 101325 0.06 x320 67 Example 1 Comparative 5 101325 0.08 x 290 63 Example 2Comparative 2 101325 0.1 xx 540 72 Example 3 *1: AC is resin layer. *2:AC is silicon nitride/oxygen nitride composite film, SiON layer. *3: ACis Cr layer. *4: UV curing

INDUSTRIAL APPLICABILITY

The gas-barrier film laminate of the present invention is extensivelyused in packaging applications in which products to be packaged arerequired to be shielded from various gases such as water vapor andoxygen, for example, for packaging foods, industrial products, medicinesor drugs, etc., to prevent deterioration thereof. Apart from for suchpacking applications, in addition, the gas-barrier film laminate is alsousable as a transparent conductive sheet or a vacuum heat-insulatingmaterial for use in liquid-crystal display devices, solar cells,electromagnetic shields, touch panels, EL substrates, color filters,etc.

1. A gas-barrier film laminate consisting of at least two gas-barrierfilm layers laminated via an adhesive layer, wherein each of thegas-barrier film layers consists of a substrate film, and at least oneconstitutive unit layer consisting of an anchor coat layer and aninorganic thin film layer formed on at least one surface of thesubstrate film in that order, and wherein the number of the bubbleshaving a diameter of at least 0.5 mm and the impurities having adiameter of at least 0.5 mm existing between the gas-barrier film layersis at most 3 in total per 100 cm².
 2. The gas-barrier film laminate asclaimed in claim 1 consisting of at least three gas-barrier film layerslaminated via an adhesive layer, wherein the number of the bubbleshaving a diameter of at least 0.5 mm and the impurities having adiameter of at least 0.5 mm existing between the gas-barrier film layersis at most 2 in total per 100 cm².
 3. The gas-barrier film laminate ofclaim 1, having a moisture permeability at 40° C. and 90% RH of at most0.02 g/m²/24 hr.
 4. The gas-barrier film laminate of claim 1, having atotal light transmittance of at least 70%.
 5. The gas-barrier filmlaminate of claim 1, wherein the substrate film is a resin selected fromthe group consisting of polyester-based resin, polycarbonate-basedresin, polymethacrylic resin, polyetherimide-based resin, polyethersulfone-based resin, cyclic olefin-based resin, and mixtures thereof. 6.The gas-barrier film laminate of claim 1, wherein the gas-barrier filmlayer has a moisture permeability at 40° C. and 90% RH of at most 0.2g/m²/24 hr.
 7. The gas-barrier film laminate of claim 1, wherein theanchor coat layer is selected from the group consisting ofpolyester-based resin, urethane-based resin, acrylic resin, isocyanategroup-containing resin, oxazoline group-containing resin,carbodiimide-based resin, alcoholic hydroxyl group-containing resin, andmixtures thereof.
 8. The gas-barrier film laminate of claim 1, whereinthe anchor coat layer is selected from the group consisting of chromium,silicon oxide, aluminium oxide, titanium oxide, silicon nitride,aluminium nitride, titanium nitride, hydrocarbon, and mixtures thereof.9. The gas-barrier film laminate of claim 1, wherein the inorganic thinfilm layer is selected from the group consisting of silicon oxide,aluminium oxide, silicon nitride, aluminium nitride, diamond likecarbon, and mixtures thereof.
 10. The gas-barrier film laminate of claim1, wherein the adhesive layer is selected from the group consisting ofurethane-based resin, polyester-based resin, epoxy-based resin, acrylicresin, and mixtures thereof.
 11. The gas-barrier film laminate asclaimed in claim 1, wherein the adhesive layer has an oxygenpermeability at 25° C. and 90% RH of at most 1000 ml/m²/24 hr/MPa. 12.The gas-barrier film laminate of claim 1, wherein inorganic particlesand/or organic particles having a mean particle size of from 0.005 to 50μm in an amount of from 0.01 to 30% by mass are present in the adhesivelayer.
 13. The gas-barrier film laminate of claim 1, wherein theadhesive layer has a surface roughness (Rms) of from 0.05 to 40 μm. 14.The gas-barrier film laminate of claim 1, which is heated or irradiatedwith energy rays in a vacuum atmosphere at 1000 Pa or less.
 15. Thegas-barrier film laminate as claimed in claim 14, wherein the energyrays are UV rays or electron rays.
 16. A method for producing agas-barrier film laminate according to claim 1 comprising: (a) a step offorming, on a substrate, at least one constitutive unit layer consistingof an anchor coat layer and an inorganic thin film layer in that order,thereby forming a gas-barrier film layer, (b) a step of laminating atleast two formed gas-barrier film layers via an adhesive layer, and (c)after or simultaneously with the lamination of gas-barrier film layers,a step of heating it or irradiating it with energy rays in a vacuumatmosphere at not more than 1000 Pa.
 17. A method for producing agas-barrier film laminate according to claim 1 comprising: (a) a step offorming, on a substrate, at least one constitutive unit layer consistingof an anchor coat layer and an inorganic thin film layer in that order,thereby forming a gas-barrier film layer, and (b) a step of laminatingat least two formed gas-barrier film layers via an adhesive layercomprising an epoxy-based resin.
 18. The method for producing agas-barrier film laminate as claimed in claim 17, wherein the adhesivelayer in the step (b) is selected from the group consisting of areaction product of (A) and (B), a reaction product of (A) and (C) and areaction product of (A), (B) and (C): (A) Metaxylenediamine orparaxylenediamine, (B) Polyfunctional compound having at least one acylgroup capable of forming an amide group moiety through reaction with apolyamine to form an oligomer, (C) Monovalent carboxylic acid havingfrom 1 to 8 carbon atoms and/or its derivative.
 19. The method forproducing a gas-barrier film laminate of claim 16, wherein the watervapor permeability (moisture permeability) at 40° C. and 90% RH throughthe gas-barrier layer is at most 0.2 g/m²/24 hr, and the oxygenpermeability at 25° C. and 90% RH through the adhesive layer is at most1000 ml/m²/24 hr/MPa.